8 THE ADVENTURES OF A NATURE GUIDE 



after each shout and noticed the direction from 

 which the reply came, its intensity, and the cross 

 echoes, and concluded that I was going down into 

 the head of a deep, forest-walled canon, and, I 



hoped, travelling eastward. 



For points of the compass I appealed to the trees, 

 hoping through my knowledge of woodcraft to 

 orient myself. In the study of tree distribution 



I had learned that the altitude might often he ap- 

 proximated and the points of the compass deter- 

 mined by noting the characteristic kinds of trees. 



Canons of east and west trend in this locality 

 carried mostly limber pines on the wall that fares 

 south and mostly Engelmann spruces on the wall 

 that faces the north. Believing that I was travel- 

 ling eastward I turned to my right, climbed out of 

 the canon, and examined a number of trees along 

 the slope. Most of these were Engelmann spruces. 

 The slope probably faced north. Turning about 

 I descended this slope and ascended the opposite 

 one. The trees on this were mostly limber pines. 

 Hurrah! Limber pines are abundant only on 

 southern slopes. With limber pines on my left 

 and Engelmann spruces on my right, I was now 

 satisfied that I was travelling eastward and must 

 be on the eastern side of the range. 



To put a final check upon this — for a blind or 

 lost man sometimes manages to do exactly the op- 

 posite of what he thinks he is doing — I examined 

 lichen growths on the rocks and moss growths on 



